This specification generally relates to sharing motion data between computer systems. Instruction that is adapted specifically to an individual user has traditionally been provided in-person. For example, to correct for quirks in a user's golf swing, a golf instructor may be present to watch the user's golf swing. Such in-person instruction can allow for the instructor to identify deviations from an optimal golf swing and to suggest correction's to the user's golf swing motion which will help the user match his/her swing more closely with the optimal golf swing.